Dr. Fernando Mazariegos first developed silver enhanced ceramic water filters in Guatemala in 1981. The filters caught on in 1994 when an organization promoting health education found that chlorine tablets were being widely rejected by rural Guatemalan communities. A group of Washington, D.C. potters concerned with peace and justice created Potters for Peace (PFP) in 1986. In 1998, Hurricane Mitch tore through Central America, leaving millions without food, water or shelter. In response, PFP began a major effort to mass-produce affordable, silver-coated ceramic water filters. Since then PFP has established ceramic water filter factories in fifteen countries around the globe. See the PFP website, www.pottersforpeace.org for more information.
A Description of the Filter Construction Procedure
The Potters for Peace filter is constructed by mixing dry clay with an organic burn material such as sawdust, wheat flour or coffee hulls. The burn material chosen varies with factory location, and is dependent upon market prices of available materials. To ensure homogeneousness, clay must be dry when it is mixed with the burn material. The burn material is sieved through two screens, such that the size range of the particles is controlled. A cement mixer is then used to mix the dry clay and sieved burn material. Water is added to this mixture, which is then molded into a flower-pot-shaped receptacle. Molding can be done by hand, on a potter's wheel, or in a hydraulic press. Potters for Peace has found that the use of a press produces the most consistent pore size within the filters, which is why we have chosen to use presses at ClaySure factories.
Next, the filter is fired at a low temperature (800-900°C). Firing causes the burn material to form small pores (0.3-4.0µm) with charcoal residues. Size exclusion of these pores removes 99% of bacteria passing through the ceramic material. The charcoal residue assists with filtration, as charcoal has antimicrobial properties. Flow rate tests are performed on each fired filter to ensure that pore size is adequate. To increase the effectiveness of bacterial removal, filters that pass the flow rate test are impregnated with colloidal silver, which has very strong antimicrobial properties. Adequate flow rates (between 1 and 2 liters per hour) ensure that contaminated water has enough contact time with the silver imbedded in the ceramic. Coated filters have been shown to be 99.98% effective in removing bacteria from water.
A Microsoft PowerPoint Presentation is available here which illustrates the filter construction procedure: Filter_Creation.ppt
How it Works
A Microsoft PowerPoint Presentation is available here which illustrates how the filter works: How_the_Filter_Works.ppt
Dr. Fernando Mazariegos first developed silver enhanced ceramic water filters in Guatemala in 1981. The filters caught on in 1994 when an organization promoting health education found that chlorine tablets were being widely rejected by rural Guatemalan communities. A group of Washington, D.C. potters concerned with peace and justice created Potters for Peace (PFP) in 1986. In 1998, Hurricane Mitch tore through Central America, leaving millions without food, water or shelter. In response, PFP began a major effort to mass-produce affordable, silver-coated ceramic water filters. Since then PFP has established ceramic water filter factories in fifteen countries around the globe. See the PFP website, www.pottersforpeace.org for more information. 